Concrete mixer



June 26, 1934. J. E. BUSHNELL CONCRETE MIXER Filed June 5, 1930 2 Sheets-Sheet 1 June 26, 1934. BUSHNELL 7 1,963,952

CONCRETE MIXER Filed June 5, 1930 -2 Sheets-Sheet 2 Patented June 26, 1934 PATENT OFFICE CONCRETE MIXER James E. Bushnell, North Plainfield, N. J., assigncr to Ransome Concrete Machinery company, Plainfield, N. J., a corporation of New Jersey Application June 5, 1930, Serial No. 459,293

1 Claim.

The present improvements relate, in general, to concrete mixing apparatus and more particularly to an improved discharge means in combi nation with such apparatus, whereby the manufacture and operation thereof is greatly improved and facilitated.

A primary object, among others, of the present improvemen':s is to provide a novel closure element in association with the discharge opening of a mixer drum, whereby sealing doors, attendant mechanism, and the undesirable features accompanying same are eliminated. A further object is to simplify the construction and operation of such closure element.

A further object is to provide a combined closure and discharge element in association with the discharge opening of a mixer drum, as well as novel means for positioning said element in a plurality of positions. Novel means for holding said elements in any desired position are also provided,

as are also means for operating said element at will from the power source for driving the drum and paver.

A still further object is to provide a novel clo- 2 'sure for the discharge opening of a non-tilting mixer drum of the type wherein means are provided for urging the contents of the drum through said opening during rotation.

Another object of the present improvements is to provide a novel closure and discharge spout for the rotating drum of a concrete mixer, which is journaled with respect to said drum, thereby facilitating the functioning of the apparatus.

A further object is to provide a drum of nontilting type so designed as to be able to handle relatively larger aggregate without the danger of the larger pieces being jammed in portions of the,

mechanism with the ensuing destruction of some parts.

Other objects and advantages of the present improvements will be apparent to those skilled in the art, upon reference to the accompanying specification and drawings, in which- Fig. 1 isa side elevation of a portion of a conlcrete mixing apparatus, embodying the present improvements;

Fig. 2 is an end elevation of the apparatus-illustrated in Fig. 1, looking toward the discharge end of the mixer;

Fig. 3 is a phantom View of the discharge end of the mixing drum;

Fig. 4 is an enlarged fragmentary view of the journal bearing.

Referring to the drawings, the mixing drum 5, having the charging inlet 6 and discharge outlet 7, is suitably mounted on mixer frame 8, for rota-5 tion about its horizontal axis. Suitable shafts and gearing are provided for imparting rotary movement from power means 9 to drum 5, said means 9 deriving energy from the power source 6 (not shown) of the mixer.

Discharge blades or wings 10 are provided in drum 5, as illustrated in Fig. 3. In use, the concrete aggregates are fed into the rotating drum 5, through opening 6, by means of charging hopper 11. Together with a sufficient amount of- Water desired, which may be charged into the drum in any desired manner, the batch is thoroughly mixed for a predetermined interval in said drum. Mixing blades (not shown) are provided, at intervals, in the drum, for facilitating the mixing function.

During the rotary movement of the drum 5, portions of the batch are caught in discharge wings 10, which constantly urge or direct the contents through the discharge opening '7, whence it drops into chute or hopper 12 to be fed into barrows, chutes for conveying the mix to the point of placement, or into other members for use in the desired manner.

The foregoing embodies the usual type nontilting drum mixer, it being common practice to provide a sealing door or other means for closing 01f discharge outlet 7 during the mixing interval, so that discharge of the contents by wings 10 is prevented until the mixing is accomplished, after which such door is opened to permit'the wings 10 to discharge the batch.

Closures of this character have been employed with varying success. The present improvements have accordingly been designed to eliminate difculties'attending the use of such closures by providing a normally open closure or barrier, so that the drum may handle relatively larger aggregate without the danger of the larger pieces being jammed in portions of the apparatus, with the attendant destruction of some parts.

Accordingly, an annular bearing housing 13 is provided about the periphery of outlet 7. This is formed, as illustrated in Fig. 4, by members 14 and 15 joined by bolts 16 to drum 5, to form an annular channel which serves as a bearing as hereinafter described.

The combined closure and discharge spout 17, comprises an elbow shaped duct, one leg 18 of which is adapted to register with opening 7, while the other leg 19, in its normal position, extends upwardly therefrom and terminates in an upturned opening 20. The inwardly extending leg of spout 17 is provided with a circumferentially extending rack or gear 21, integral with the spout or otherwise fixed thereto. An outwardly extending flange 22 is provided adjacent the inlet portion of spout 1'7 and serves as a bearing surface, whereby the spout may be journaled in the channel shaped bearing 13. This assembly is illustrated in detail in Fig. 4, wherein annular packing rings 22 are shown disposed between the relatively moving bearings 13 and 22 to facilitate rotation.

As more clearly illustrated in Fig. 2, a shaft 23 is disposed across the mixer frame and is supported so as to be rotated at will. A portion of said shaft is provided with a worm 24, which is in mesh with gear 21 of the spout 17. The interengagement of these parts accordingly provides means for maintaining spout 1'7 in any given position, resisting any rotary motion which may be transmitted thereto by drum 5.

A beveled gear 25, keyed or otherwise fixed to shaft 23, is in mesh with a similar gear 26 suitably journaled in bearing 27. Mechanism for imparting rotary motion to these gears, worm 24, and spout 17, is provided by the clutch device 3 28, which may be manually or otherwise operated to connect the aforementioned parts to shaft 29 of the mixer drum rotating mechanism. Accordingly, by suitable operation of the clutch 28, power from power source 9 may be transmitted to gear 21 for rotating spout 17 at will.

In operation, the spout 17 is normally disposed in the full line position of Figs. 1 and 2. The driving mechanism for the spout is disconnected from the power source by clutch 28. Upon rotation of drum 5, the materials to be mixed may be charged thereinto by hopper 11 and the mixing period begun. During this period and at all times (except as hereinafter mentioned) the spout 17 remains upwardly disposed, while the drum rotates with respect thereto through the provision of the journal bearings.

Accordingly, the portions of the batch which are constantly being urged through opening 7 by wings 10, are met and caught by the upwardly directed lower wall 7 of spout 1'7, whence the aggregates or portions of the batch, drop back by gravity into the drum through opening 7, to be further mixed.

This function of spout 1'7 is performed constantly throughout the mixing period and so long as said spout remains in an upwardly directed position, the materials thrown into it by wings 10,'will invariably be returned to the drum 5. In this position, therefore, the spout serves as a barrier or closure preventing any discharge of the contents of the drum during the mixing interval.

It is notable, furthermore, that the present improvements contribute to a more thorough mixing of the batch, since the expulsion of the materials by the wings 10 into spout 1"], their return by gravity to the drum and the constant repetition of this cycle with the attendant turning over of the ingredients, promotes a more efiicient and thorough mix.

To discharge the contents of the drum, after the mixing interval has transpired, the clutch 28 may be thrown to connect the spout driving mechanism to power shaft 29, whereby the spout same, transmitted by the rotating drum 5.

The present improvements are more particularly adapted for use in large capacity mixers, preferably of the stationary type, wherein four or five cubic yards of concrete may be prepared. In such equipment, it is desirable and possible to employ large aggregate, providing no injury to the mechanism results.

During the mixing interval as well as during the discharge of the aggregate, it is notable that the spout 17 and blades 10 remain in the same relative position laterally. Therefore, there is the same clearance between the revolving bladesand the spout for accommodating large aggregates, during discharging as there is during mixing operation.

Accordingly, the probability of aggregates becoming lodged between the discharge chute and the revolving blades, thereby shearing or injuring one or the other is minimized or totally eliminated. This feature is of marked importance and cannot be over emphasized.

After effecting the drum discharge in the foregoing manner, the clutch may again be actuated to rotate spout 17 to full line position, in preparation for mixing another batch. It is notable that the journal bearing provided between spout 1'7 and drum 5, not only affords free relative movement of these elements, but also serves to support and sustain the spout in proper position.

Accordingly the novel design of the present improvements provides a single element which serves the double purpose, in one position, of returning the contents of the discharge wings 10' to the drum proper, whereupon the material so returned is again brought into the action of the mixing members, and in another position, of catching the discharged materials from the wings and passing it out of the mixer. Q

Various modifications Within the scope of the present improvements will be apparent to those skilled in the art. It is understood that the invention is not limited to the particular construction and arrangement shown and described herein.

I claim A concrete mixing device comprising a rotat- 

